As shown in FIG. 9, an air pump (8) according to the first example of the prior art has a pump body (81) with a spring (82) received inside. The pump body (81) is made of flexible material, such as PVC, and can be flattened.
While operating the air pump (8), the user depresses it to discharge the air inside, through an air outlet (84), so that the pump body (81) is flattened and the spring (82) is compressed. Then, he releases the air pump (8). The pump body (81) is automatically restored under the action of the spring (82). Also, outside air is sucked into the air pump (8) through an air inlet (83). By repeating the above operations, the air pump (8) can continuously supply air.
Check valves are necessarily provided in the air inlet (83) and air outlet (84) in order to control the air to flow in a single direction. It is understood that various check valves can be used in the air pump (8) and are therefore not shown in FIG. 9.
Unfortunately, the pump body (81) made of flexible material is easily pricked by the spring (82) which is generally made of steel. Further, the air pump (8) cannot readily be packaged for sale and transport.
FIG. 10 shows another air pump (9) according to the second example of the prior art, in which a foam (92) is received in the pump body (91) of the air pump (9) and a bore (921) is provided in the foam (92). Reference numbers (93) and (94) are an air inlet and an air outlet.
The foam (92) has many pores itself and is elastic. When the user depresses the air pump (9), both the foam (92) and the pump body (91) are flattened. The air in the pores of the foam (92) is pushed out and is discharged to the outside of the air pump (9) through the air outlet (94). When the user releases the air pump (9), the foam (92) regains its original shape due to its own elasticity and outside air is sucked in the foam (92) through the air inlet (93) and the bore (921).
In this example, the foam (92) is expensive and requires a great deal of storage space. Moreover, the force applied to depress the foam (92) may cause permanent deformation to the foam (92) so that the air pump (9) fails to function properly.
An object of the present invention is to provide an air pump to overcome the problems of the prior art. The air pump of this invention comprises a hollow pump body, at least one pulling member, an air inlet and an air outlet. The hollow pump body has air inside and consists of flexible sides and two opposite stiff ends. The air outlet is provided on the pump body to discharge the air in the pump body when the pump body is pressed. The pulling member is attached to one of the stiff ends of the pump body in order to restore the pressed pump body to its original shape by pulling the pulling member. The air inlet is provided on the pump body to suck outside air into the pump body when the stiff end is pulled by the pulling member to restore the pressed pump body shape.
Alternatively, the air pump comprises a hollow pump body, an air inlet and an air outlet. The pump body has air inside and consists of flexible sides, a first and second curved ends which are stiff. The air outlet is provided on the first curved end (or at any proper position of the pump body) to discharge the air in the pump body when the first and second ends are pressed to flatten the pump body. The air inlet is provided on the second curved end (or at any proper position of the pump body) to suck outside air into the pump body when the first and second ends are pulled to restored the shape of the pump body.
Alternatively, the air pump of this invention comprises an inflatable pump body, an air inlet and an air outlet. An air chamber is formed and surrounded by the inflatable group body. The inside of the pump body is divided into a first air cell and a second air cell with an opening provided therebetween, and the air chamber and the first air cell respectively have a first air and a second air inside. The air outlet is mounted on the pump body to discharge the first air in the air chamber when the pump body is pressed by a force. The air inlet is mounted on the pump body to suck outside air into the air chamber when the force is released. The second air in the first air cell is pushed into the second air cell through the opening when the pump body is pressed by the force, and automatically flows back to the first air cell through the opening when the force is released.